Touch sensing technology capable of providing a natural interface between an electronic system and user has found widespread applications in a variety of fields, for example, in mobile phones, personal digital assistants (PDAs), automatic teller machines (ATMs), game machines, medical devices, liquid crystal display (LCD) devices, light emitting diode (LED) devices, plasma display panel (PDP) devices, computing devices, and the like, where a user may input desired information and/or operate the electronic system through a touch sensing device associated with the electronic system. A touch sensing device typically includes a touch panel which has a plurality of touch modules spatially arranged in the form of a matrix with a plurality of rows and a plurality of columns, a driving unit coupled to the touch panel via a plurality of driving lines, and a sensing unit coupled to the touch panel via a plurality of sensing lines.
FIG. 10 shows a conventional touch sensing device 10. The touch sensing device 10 includes a touch panel 11, a sensing unit 12, and a driving unit 15. As an illustrative example, the touch panel 11 has fifteen touch modules 11a arranged in the form of a matrix comprising three rows and five columns. The touch panel 11 is coupled to the driving unit 15 via three driving lines 14, with each driving line corresponding to a respective row of touch modules. The touch panel 11 is coupled to the sensing unit 12 via five sensing lines 13, each sensing line corresponding to a respective column of touch modules. The sensing unit 12 includes five sensing devices 12a, with each sensing device adapted for detecting a sensing signal in response to a driving pulse applied to a respective touch module 11a in a respective column. The driving unit 15 provides three trains of driving signals 16. Each train of driving signals 16 is applied to a respective driving line 14, and comprises five pulses, with each pulse for a respective touch module 11a in a corresponding row. The trains of driving signals 16 are delayed successively from row to row so that sensing signals from the touch modules are detected by the sensing devices in a row by row fashion to ensure correct determinations of sensing positions. FIG. 11 shows schematically a capacitive touch module 11a coupled with a driving line 14 and a sensing line 13. The driving line 14 and the sensing line 13 are coupled via a first capacitor 19. Referring to FIG. 11(A), when the touch module 11a is not touched, the touch module 11a is open. Referring to FIG. 11(B), when the touch module 11a is touched, the touch module 11a is coupled to the driving line 740 via a second capacitor 20. FIG. 12 shows a block diagram of the conventional touch sensing device 10 illustrated in FIG. 5. The driving unit 15 applies a driving signal 16 to a driving line 14 that is coupled to a sensing line 13 via a capacitor 19. A sensing signal is detected and transmitted, via the sensing line 14, to a comparator 17. The comparator 17 compares the sensing signal with a reference signal from a data buffer 18 to determine if the corresponding touch module has been touched or not.
The conventional touch sensing device illustrated in FIGS. 10-12 has the disadvantages that the number of driving signals provided by the driving unit is proportional to the number of rows in the touch panel. As the touch sensing technology continues to advance for higher and higher resolution, the number of driving signals required increases proportionally, and so does the complexity and the cost of the driving unit.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.